Furosemide is 4-chloro-N-furfuryl-5-sulfamoylanthranilic acid. It is recognized in United States Pharmacopeia (USP) as a diuretic and used in medical practice as a diuretic, antihypertensive and antihypercalcemic agent. Its usual pharmaceutical dosage forms are Furosemide Injection, containing 10 mg per ml of furosemide as the sodium salt, and Furosemide Tablets, declaring 20-, 40- or 80-mg per tablet of furosemide.
Injection and tablet dosage forms, which are highly objectionable to many patients, are employed to administer furosemide because of its low solubility in water. Furosemide is listed in USP as being practically insoluble in water, which denotes a solubility less than 0.1 mg per ml.